Continuity mistake: When Roy heads back into the dish to rescue Helen, he brings his remote with him. However, later on when the scene cuts to the kids watching their parents on the TV, the remote is seen on the table in front of them.
Other mistake: When Daryl climbs over the fence to get power from the neighbors' house, he attaches car jumper cables to the house power box. We saw on his way over that the other end of the cable isn't connected to his house yet. Attaching the cable to the terminals should not have made any spark unless the other end of the cable clamps were touching.
Visible crew/equipment: Near the end of the film when Spike is hanging from the chandelier; Crowley is shown to be in a suit of armor. When he starts to hop away to cut down the chandelier with an ax; the left leg of the suit of armor that is left behind, falls over. After it has fallen, you can see a small metal rod being retracted into the floor. This rod was obviously being used to hold the leg into place until it was supposed to fall over.
Continuity mistake: During the music video for "Start Me Up," one of the dancers accidentally turns down the volume to the music, and we see the "Volume" status bar on the screen decrease. The dancers stop and act confused until one of them turns the volume back up again. The problem is, the "Volume" bar on the screen gradually increases, yet we hear the sound come back suddenly, as though someone just pressed a "mute" button.
Visible crew/equipment: The scene where Daryl's bike is about to be sucked into the dish. He is lifted into the air and you see two hands holding him up under his armpits. (00:33:17)